The present invention pertains to a composite mattress system and, more particularly, to such a system which is primarily for institutional use, such as in hospitals, nursing homes and the like, and it is also adapted for domestic use, such as in convertible sofas. In institutional type mattresses, it is well-known that the supporting springs or pans on beds used in hospitals and similar institutions, require bending or flexing of the mattresses due to the supporting spring sections or pans being articulared and relatively movable between, for example, a relatively flat condition and one in which the mattress sections or pans are disposed at angular relationships, such as supporting the back of a patient at an angle to the horizontal, having the knees raised, or in some situations, even having the supporting sections of the bed disposed somewhat as a chair. All of these arrangements usually require that the mattress be capable of being folded along the lines where the springs or pans are flexibly connected for disposing the same in desired angular relationship, and in convertible sofas, similar or even more acute reverse folding also is required.
It also is a desirable factor that the mattresses be comfortable, even though subjected to bending at the articulated connection of the bed spring or pans, and in order to provide adequate comfort, it has been customary to employ mattresses of reasonable thickness, such as of the order of five or six inches or more. Attempting to bend or fold mattresses of this thickness however, presents problems, such as inability to conform closely to the angularly related sections, particularly at the location where the mattress is bent, or the mattress becomes puckered and over a period of time, becomes worn in the sections where it is bent. Further, if a mattress of the exemplary thickness referred to above is not used, and instead, a thinner mattress is employed which would readily be subjected to bending, the thin nature of such mattresses minimizes comfort to the occupant of the bed due to, for example, the mattress "bottoming-out", which is a term commonly known in the mattress industry and refers to the situation where the imposition of a weight, such as a human body upon the mattress, initially is cushioned but, depending upon the amount of the weight, said weight often compresses the mattress to an extent that no further resilience is offered and the support is the same as if the mattress were simply a rigid, immovable surface. The ideal arrangement is one in which when the weight applied to the mattress reaches stability, there is still at least a limited amount of further yieldability and a sensation of contacting an immovable surface is not present.